After the chaos caused by drone sightings at London Gatwick Airport between December 19 and December 21 last year, both London Heathrow and London Gatwick Airport have invested heavily in military-grade anti-drone equipment to ensure that further levels of disruption from the presence or suspected presence of drones can be avoided.

There were sightings of drones over the three days at London Gatwick, the chief constable of Sussex police, Giles York, confirming that officers had received 115 reports of sightings in the area, including 93 that had been confirmed as coming from “credible people” including a pilot and airport staff.

As a consequence of the disruption, around 140,000 passengers were affected as approximately 1,000 flights were canceled.

At the time, to enable Gatwick to become operable again, the Israeli-developed Drone Dome system, which can detect and jam communications between a drone and its operator, was deployed.

While spokespersons for both London Gatwick and Heathrow Airports have confirmed that state-of-the-art military-grade anti drone systems have been installed, no further details of the specific type have been revealed.

Many other airports in the U.K. are now investigating the opportunity to install similar, but smaller anti-drone systems. It is believed that the cost of the new anti-drone systems at the U.K.’s two largest airports cost £5m (US$6.2m) per installation.